... Another symptom, which can make people really think "stroke", is an inability to form words. I've had times where I could get the first half of a word, but the second half would be nonsense. Once I lost all ability to think in English. That was very weird because we constantly think in words. ... (3 replies)

... eing said, since you've had this problem for a number of years and your vision is relatively ok between episodes, I would guess it's a migraine aura. You can get the aura without getting a headache. So, do some research on migraine aura and scintillating scotoma. ... (3 replies)